It has been hypothesized that a lack of self-control may underlie certain disorders, such as ADHD or substance abuse. Therefore, much research has focused on understanding the neural mechanisms behind self-control, how it is impaired, and how it affects performance in various situations. One theme of this research in humans is that self-control may be a single concept and different forms of control are related, both behaviorally and neurally. In support of this, the right ventral lateral prefrontal cortex (rVLPFC) is consistently recruited in various control tasks. What is missing in this line of research, however, is how impaired self-control relates to normal self-control and a systematic study of how general the concept of self-control really is. The goal of this dissertation was to fill in the gaps of self-control research.
The first study explored the development of motor control in two different contexts during functional MRI. Motor control improved with age. We also found that although different versions of the task showed unique neural components, both behavioral performance and control-related neural activity were consistent across the two contexts.
The second study extended those findings to look at motor control in two different contexts within a single group of participants. We compared motor control during performance of a novel, controlled task to motor control during that same task in an overlearned, automatic condition. Context in the form of automaticity did not influence motor control ability.
The last study examined four different forms of self-control in a single context to determine whether multiple forms were related in a single sample of healthy adults. Participants were tested on motor control, control over risk-taking behavior, control to be able to delay gratification, and emotional control during an MM scan. Behavioral performance across the tasks was not related, but it was related to self-report questionnaires of impulsivity and risk-taking. Crucially, we found overlap in the rVLPFC across all four tasks.
Taken together, these studies imply that although there is sonic overlap of different forms of self-control, there are aspects of control that can be dissociated from each other, thus it is not a singular concept. Helping to improve our understanding of the mechanisms behind self-control may help us to better understand what goes wrong in disorders where it is impaired.